The present invention concerns a method for calibrating at least one processing element, in particular at least one temperature sensor of a processing station, and a corresponding device for calibrating at least one processing element, in particular at least one temperature sensor of a processing station, and a device for beating plastic preforms.
The method described herein comprises a first step in which initially a measurement preform is provided and then, by means of at least one measuring element, at least one first measurement value of the measurement preform is measured before or after its processing by a processing station for processing plastic preforms.
This may mean that, following measurement, the measured value is subjected to an in particular mathematical processing in order to be able to subject the measured values to further detailed analysis.
The measured value may be a pressure value, a temperature value, a force value, a moment value, a position value, a time duration, a flow quantity, a format value, a speed value, a radiation value (e.g. microwave radiation), in particular a radiation intensity value, and/or a germ count. In other words, the at least one measuring element may be configured to measure a pressure value, a temperature value, a force value, a moment value, a position value, a time duration, a gas or liquid quantity (e.g. a volume value), a speed, a radiation intensity or field strength, and/or a germ count. The measuring element may in particular comprise several measurement sensors, wherein each of the measurement sensors may determine or measure one or more of the above-mentioned values. In particular, the measuring element may comprise several measurement sensors of the same type.
The format value stands in particular for certain geometrical or chemical values which relate to one or more geometric parameters or a material composition of bottles or preforms to be produced, and which in turn may be assigned to specific format parts, in particular processing units, of the blowing machine, the filling machine and/or the labelling apparatus.
The at least one measurement value may in particular correspond to a physical processing parameter of containers (preforms and/or bottles) in a blowing machine, a filling machine (filler) and/or a labelling apparatus.
The measuring element may for example therefore comprise, for temperature measurement, optical and/or electrical temperature sensors which measure, in contact with the measurement preform or also contactlessly, the respective electromagnetic radiation emitted by the measurement preform, in particular heat radiation. Also, the measuring element may comprise a processing and storage unit by means of which the measured temperature values are stored and processed.
However, this publication does not achieve the objective that, in a plant comprising several parallel individual processing stations of the same type, the stations must be calibrated to each other in order to deliver a uniform output.
Individual processing stations, i.e. individual process treatment stations, for example microwave ovens, namely usually form a closed system which can normally perform its process autonomously.
If for example several of these stations are combined into a plant e.g. on circulating conveyors, the temperature sensors of the individual stations must be synchronised with each other to avoid an offset between stations which would then be reflected in the quality of the output. In this context, the term “offset” describes any parameter-dependent and parameter-defined deviation from a standard operating value or standard operating range. Temperature sensors, above all contactless temperature sensors e.g. pyrometers, react very sensitively to changes in the process and their environment. Component tolerances, background radiation, temperature changes on the sensor housing, different emission values, ageing influences and many other influence factors affect the measurement accuracy of the temperature sensors.
In the case of a plurality of stations, these factors may vary in intensity, which can then lead to a greater or lesser measurement inaccuracy in the respective stations.
To this extent, the prior art has been unable to offer a facility for adapting the individual processing stations within a plant, for example for processing plastic preforms, on the basis of a pre-selected standard curve in order to minimise the individual deviations described above from such a common selected standard curve.